string.php

xiaoxiao2025-07-18 7

<?php /** * Created by PhpStorm. * User: dllo * Date: 16/8/8 * Time: 上午11:47 */ header("Content-type:text/html;charset = utf-8"); $a = 50; // 在php中双引号中的变量可以被解析,但是单引号内不能解析 // 双引号中变量要加大括号 $str = "小熊的年龄是{$a}岁"; $str2 = '$a'; echo $str; echo "<hr>"; echo $str2; // 定界符 $str3 = <<<EOF 今天天气不错好像没雨 EOF; echo $str3; // 字符串拼接 echo "大水杯"."大书包"; echo "<br>"; // php中的+只能做运算,不能拼接 // 计算时,如果有字符串,从前向后找数字,第一位如果不是数字,则不运算 echo "20" + 20 + true + "a12"; // &取址符:表示变量b与变量a共用同一个地址,相当于一个别名 // 所以修改任意一个变量的值,另一个也会相应改变 $a = "里约"; $b = &$a; echo "<hr>"; echo $b; $b = "北京"; echo $a; // 字符串比较(ASCII比较) echo strcmp("c","a"); echo "<hr>"; //字符串长度 echo strlen("a"); echo "<hr>"; // 字符在字符串中的位置 echo strpos("helloworld","o"); // 如果字符串中不存在,返回false var_dump(strpos("helloworld","a")); // 小写 echo strtolower("HELLO"); // 大写 echo strtoupper("world"); // 字符串分割为数组,第二个参数为每几个字符为一组 var_dump(str_split("helloworld",3)); echo "<hr>"; // 字符串截取,三个参数: // 1.要截取的字符串 // 2.开始位置 // 3.截取个数,默认到结尾 echo substr("helloworld",3,2); echo "<hr>"; // 重复多少个字符 echo str_repeat("a",20); echo "<hr>"; // 字符串替换,三个参数 // 1.要被替换的字符串 // 2.替换为这个字符串 // 3.整个string echo str_replace("o","a","helloworld"); echo "<hr>"; // 忽略大小写替换 echo str_ireplace("O","b","hellOworld"); // 输出完整的html标签 echo htmlspecialchars("<hr>"); echo "<hr>"; // 去掉空格 echo "/".trim(" abc ")."/"; echo "<hr>"; // 去掉左边空格 echo "/".ltrim(" abc ")."/"; echo "<hr>"; // 去掉右边空格 echo "/".rtrim(" abc ")."/"; echo "$"; echo "\"\""; echo "<hr>"; for ($i = 1; $i <= 5; $i++) { for($j = 1; $j <= $i * 2 - 1; $j++){ echo "*"; } echo "<br />"; } echo "<hr>"; $a = 10; $b = &$a; echo $b; echo "<hr>"; $b = 15; echo $a; echo "<hr>"; $val_1 = 'hello'; $$val_1 = 'world'; echo $hello; echo "<hr>"; echo $val_1; echo "<hr>"; echo ${$val_1}; $i=10; $i++; echo $i; echo "<hr>"; $y = $i++; echo $y; echo "<hr>"; $y = ++$i; echo $y; echo "<hr>"; $y += 10; echo $y; $a = "123"; $a .= 456; echo "<hr>"; echo $a; $a = 3; $b = 4; $c = 5; echo "<hr>"; echo $a > $b && $c>$b || $a<$c; $a = 3; $b = 4; $c = 5; echo "<hr>"; echo $a>$b ? $a : $c; echo "<hr>"; $x = 1; ++$x; $y = $x++; echo $y; echo "<hr>"; function abc($a,$b=10,$c=10) { return $a+$b+$c; } echo abc(10,30); echo "<hr>"; function a(&$a) { $a *= 10; } $b = 10; a($b); echo $b; echo "<hr>"; function keep_val(){ static $count = 0; $count++; echo $count; } keep_val(); echo "<hr>"; keep_val(); echo "<hr>"; keep_val(); echo "<hr>"; $str1 = null; $str2 = false; echo $str1==$str2 ? '相等' : '不相等'; echo "<hr>"; $str3 = ''; $str4 = 0; echo $str3==$str4 ? '相等' : '不相等'; echo "<hr>"; $str5 = 0; $str6 = '0'; echo $str5===$str6 ? '相等' : '不相等'; echo "<hr>"; $count = 5; function get_count(){ static $count = 0; return $count++; } echo $count; ++$count; echo "<hr>"; echo get_count(); echo "<hr>"; echo get_count(); echo "<hr>"; $GLOBALS['var1'] = 5; $var2 = 1; function get_value(){ global $var2; $var1 = 0; return $var2++; } get_value(); echo $var1; echo "<hr>"; echo $var2; echo "<hr>"; $num = 6 + false + null + "24linux"; echo $num; echo "<hr>"; for($i = 1; $i <= 13; $i++){ if($i == 6 || $i == 9){ continue; } echo $i.",&nbsp"; } echo "<hr>"; $i = 0; while($i < 13){ $i++; if($i == 6 || $i == 9){ continue; } echo $i.",&nbsp"; } echo "<hr>"; $i = 0; do{ $i++; if($i == 6 || $i == 9){ continue; } echo $i.",&nbsp"; }while($i < 13); echo "<hr>"; for($i = 1; $i <= 100; $i++){ if($i % 2 == 0){ continue; } echo $i."&nbsp"; } echo "<hr>"; $i = 0; while($i < 100){ $i++; if($i % 2 == 0){ continue; } echo $i."&nbsp"; } echo "<hr>"; $i = 0; do{ $i++; if($i % 2 == 0){ continue; } echo $i."&nbsp"; }while($i < 100); echo "<hr>"; function maxNumber($a,$b,$c){ return ( $a > $b ? $a : $b ) > $c ? ( $a > $b ? $a : $b ) : $c; } echo maxNumber(3,5,8);

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